Mail Screening Apparatus

ABSTRACT

A mail screening apparatus is provided to perform the inspection of mail or similar objects. Terahertz inspection is used to localize potential suspicious areas by imaging the contents inside the envelope or small parcel. The mail screening apparatus includes a primary and a secondary inspection zone, preferably allowing inspection of the mail in a normal and a zoomed mode, respectively. The same light source, image capture device and intervening optical components are used in both normal and zoomed modes. Metal detection may optionally be used to enhance awareness in the presence of metallic content. In one implementation, metal detection zones are provided in an orthogonal configuration with respect to the primary inspection zone used for terahertz imaging to accommodate for both manual and automatic inspection of mail.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/292,035 filed Mar. 4, 2019, which is a continuation of U.S.application Ser. No. 15/388,956 filed Dec. 22, 2016 (now U.S. Pat. No.10,247,842 issued Apr. 2, 2019), which claims the benefit of priority ofU.S. provisional Application No. 62/387,592 filed Dec. 23, 2015, thedisclosures of which are incorporated herein by reference in theirentireties.

TECHNICAL FIELD

The technical field generally relates to live screening of mail.

BACKGROUND

Live mail screening is a technique which allows seeing through envelopesand small parcels, enabling the detection of suspicious items such aspowders or electrical circuits prior to opening the mail and exposingthese contents. It is known in the art of mail screening to useradiation in the long terahertz (THz) wavelengths, for example between700 μm and 1075 μm, as the penetration depth of the THz radiation islong enough to see through envelopes and small parcels.

There remains a need in the field for a practical and efficientapparatus for screening mail or similar small objects.

SUMMARY

In accordance with one aspect, there is provided a mail screeningapparatus to perform the inspection of mail or similar objects.Terahertz inspection is used to localize potential suspicious areas byimaging the contents inside the envelope or small parcel. The mailscreening apparatus includes a primary and a secondary inspection zone,preferably allowing inspection of the mail in a normal and a zoomedmode, respectively. The same light source, image capture device andintervening optical components are used in both normal and zoomed modes.

Metal detection may optionally be used to enhance awareness in thepresence of metallic content. In one implementation, metal detectionzones are provided in an orthogonal configuration with respect to theprimary inspection zone used for terahertz imaging to accommodate forboth manual and automatic inspection of mail.

In one embodiment there is provided a mail screening apparatus includinga casing having a base and a top housing mounted over the base in aspaced-apart relationship. The base and the top housing define a mailinspection bay therebetween having a primary inspection zone and asecondary inspection zone. The base includes an inspection counter forsupporting a piece of mail to be screened at either one of the primaryand secondary inspection zones. The inspection counter allows lighttherethrough at the primary and secondary inspection zones.

The mail screening apparatus further includes a light generatingassembly mounted in the top housing and configured to generate aninspection light beam having an optical frequency in the terahertzfrequency range. The light generating assembly is further configured toproject the inspection light beam into the base through the primaryinspection zone.

The mail screening apparatus further includes a light redirectionassembly provided in the base and configured to redirect the inspectionlight beam entering the base from the primary inspection zone to emergethrough the secondary inspection zone and project towards the tophousing.

A light collecting assembly is mounted in the top housing and configuredto receive and detect the inspection light beam projected from the basethrough the secondary inspection zone. Finally, the mail screeningapparatus includes a focus adjusting mechanism operable to adjust afocus of the light collecting assembly on either one of the primary orthe secondary inspection zones.

In some implementations, the optical frequency of the inspection lightbeam corresponds to a wavelength between 700 μm and 1075 μm.

In some implementations, the light generating assembly includes a lightsource generating the inspection light beam and a beam conditioningassembly configured to transform the spatial energy distribution of theinspection light beam from a Gaussian initial shape with an ellipticalfootprint to a flat-top final shape with a rectangular footprint.

Optionally, the top housing may include an output window made of atransparent material positioned across a path of the inspection lightbeam towards the primary inspection zone, and an output window made of atransparent material positioned across a path of the inspection lightbeam into the top housing through the secondary inspection zone. Theinspection counter may have a primary inspection window made of atransparent material and extending along the primary inspection zone.Preferably, the primary inspection window has a lens curvature. Theinspection counter may further have a secondary inspection window madeof a transparent material and extending along the secondary inspectionzone.

In some implementations, the light redirection assembly may include apair of folding mirrors mounted at opposite 45° angles with respect to aplane of the inspection counter.

In some implementations, the light collecting assembly includes a cameraobjective having a focus controllable by the focus adjusting mechanism.The focus adjusting mechanism may for example be embodied by a rotatinghandle operatively connected to the camera objective.

In some implementations, the light collecting assembly may furtherinclude an image capture device positioned to receive and detect theinspection light beam collected by the camera objective. The imagecapture device may for example be embodied by a 2D image sensor.

In some implementations, the mail screening apparatus may furtherinclude an electronic board configured to perform control functionsincluding acquiring image data from the image capture device andpreprocessing and formatting said image data. A processing unit may beconnected to the electronic board and configured to perform apostprocessing of the image data. In some embodiments, a display may beintegrated in a front portion of the top housing and operativelyconnected to the processing unit to receive the postprocessed image datatherefrom.

In some implementations, the mail inspection bay may further include atleast one metal detection zone. For example, the mail inspection bay mayinclude a first and a second metal detection zone orthogonally disposedwith respect to the primary inspection zone, the secondary inspectionzone extending on a side of the primary inspection zone opposite thefirst metal detection zone.

Other features and advantages will be better understood upon a readingof preferred embodiments thereof with reference to the appendeddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are front and rear isometric views of a mail screeningapparatus according to an embodiment.

FIG. 2 is a rear isometric view in partial transparency of the mailscreening apparatus of FIGS. 1A and 1B.

FIG. 3 is a front isometric view in partial transparency of the mailscreening apparatus of FIGS. 1A and 1B.

FIG. 4 is a side view in partial transparency of the mail screeningapparatus of FIGS. 1A and 1B.

FIG. 5 is a front view in partial transparency of the mail screeningapparatus of FIGS. 1A and 1B.

DETAILED DESCRIPTION

Referring to FIGS. 1 to 5, there is shown a mail screening apparatus 20according to one embodiment. In the illustrated embodiment the mailscreening apparatus 20 advantageously combines metal detection and THzimaging to perform the inspection of the mail. The THz inspection aspectis used to obtain an image of the contents inside the envelope or smallparcel, to localize potential suspicious areas. The metal detection zoneis used to enhance awareness in the presence of metallic content.

It will be readily understood that variants of a mail screeningapparatus such as described herein may be used for the screening of mailof various types such as envelopes, small parcels and the like.

Referring more particularly to FIGS. 1A and 1B, in some implementations,the mail screening apparatus 20 is a stand-alone device incorporatingall of the components described below in a single casing 100.Preferably, the casing 100 includes a base 102 and a top housing 104mounted over the base 102 in a spaced-apart relationship, for exampleusing frame members such as a pair of frame posts 106. The free spacebetween the base 102 and the top housing 104 defines a mail inspectionbay 108. The mail inspection bay 108 is preferably large enough to allowthe inspected mail to be handled within the bay. The top wall of thebase 102 defines an inspection counter 110 on which mail to be inspectedcan be placed. The inspection counter 110 is separated into differentinspection zones, including a primary inspection zone 42 and a secondaryinspection zone 50. The inspection counter 110 can support a piece ofmail to be screened at either one of the primary and secondaryinspection zones 42 and 50. As explained further below, the inspectioncounter 110 allows light therethrough at the primary and secondaryinspection zones 42 and 50. An opening in the back central section ofthe base 102, here defined by the free space between the frame posts106, allows for an optional conveyor belt (not shown).

Referring to FIGS. 2 and 3, the mail screening apparatus 20 includes alight generating assembly 23 mounted in the top housing 104 andconfigured to generate an inspection light beam 24 and project theinspection light beam 24 into the base 102 through the primaryinspection zone 42. in the illustrated embodiment the light generatingassembly 23 first includes a light source 22 mounted within the tophousing 104 and emitting the inspection light beam 24 (referred tohereinbelow as the “light beam” for simplicity). In someimplementations, the light source 22 emits light at an optical frequencyin the terahertz range, for example at a frequency corresponding to awavelength between 700 μm and 1075 μm. In some implementations theoptical frequency of the inspection light beam may correspond to awavelength between 50 μm and 3 mm. It will be readily understood by oneskilled in the art that the term “light source” is meant to encompassstand-alone devices as well as more complex optical assemblies orsystems comprising a plurality of components cooperating together toprovide the desired light beam. An example of commercially availablelight sources that may be used in some implementations includes a Gunnoscillator from Sage Millimeter Inc. combined with frequency doublersand triplers from Virginia Diodes Inc. emitting above 2 mW at awavelength of 1.06 mm, with an antenna also from Virginia Diodes. Inother embodiments, the light source may for example be a Schottky diodeor a GaAs diode emitting radiation at a suitable wavelength.

The light generating assembly 23 may next include any number of opticalcomponents in a path of the light beam 24 for shaping, collimating andredirecting the light beam 24. In the present example the lightgenerating assembly 23 includes a beam conditioning assembly 25 withinthe top housing 104 which shapes and expands the transverse irradianceprofile of the optical beam 24 radiated by the light source 22. In oneimplementation the light beam 24 has a footprint between 125 mm and 400mm. In some implementations, the beam conditioning assembly 25 may favora uniform irradiance distribution along the transverse plane of thelight beam 24. Examples of beam conditioning devices suitable for thispurpose are disclosed in the U.S. patent application entitled “BEAMCONDITIONING DEVICE” filed concurrently with the present application andnaming Michel Doucet, Alain Bergeron and Linda Marchese as inventors,the contents of which being incorporated herein by reference in itsentirety.

In the illustrated embodiment of FIG. 2, the beam conditioning assembly25 includes a convex mirror 34 and a concave mirror 36 successivelydisposed in a path of the light beam 24. The shapes of the convex andconcave mirrors 34 and 36 are preferably computed to transform thetransverse spatial energy distribution of the light beam from a Gaussianinitial shape with an elliptical footprint, as typically characterizinglight beams emitted from the type of light source used herein, to aflat-top final shape with a rectangular footprint. The local curvatureof the convex mirror 34 is designed to control the intensitydistribution of the light beam. The concave mirror 36 reflects thedivergent light beam 24 from the convex mirror 34 so that, as a result,the light beam 24 reflected off the concave mirror 36 is collimated andhas a propagation axis parallel to its propagation axis prior toreflection on the convex mirror 34.

The beam conditioning assembly 25 may further include a first mirror 26positioned at an angle of 45° with respect to the propagation axis ofthe light beam 24 impinging thereon from the light source 22 upstreamthe convex and concave mirrors 34 and 36. It will be noted that forclarity, the portion of the light beam 24 extending between the lightsource 22 and the first mirror 26 is not shown, replaced instead by thevirtual image 22′ of the source on the side of the first mirror 26opposite its reflecting surface 28. In some implementations (notillustrated), the first mirror 26 may be a coherence-breaking mirrorhaving a reflective surface provided with a structured pattern (notshown). The structured pattern may for example be composed of aplurality of sloped elements distributed over the reflecting surface,each sloped element deviating the beam component of the light beamincident thereon at a slightly different angle than the deviationimparted on neighboring beam components by neighboring sloped elements.Reflection of the light beam by the sloped element therefore breaks thespatial coherence of the light beam. The slope of each sloped elementmay be computed to deviate the beam component of the light beam incidentthereon by an angle smaller than the divergence of the light beam. Infurther variants, the coherence-breaking mirror may be mounted on arotating mount (not shown), preferably operated by a motor. In thisvariant, the coherence-breaking mirror is therefore rotatable about arotation axis normal to its reflecting surface, thus breaking thetemporal coherence of the light beam reflected thereon.

In the illustrated embodiment of FIG. 2, a collimating lens 33 isdisposed on the optical path downstream the reflection on the firstmirror 26. The collimating lens 33 may for example be embodied by aspherical or aspherical lens, and transforms the light beam 24 into aslowly-diverging beam. It will be readily understood that otherconfigurations can be considered and that additional optical elementsmay be provided in the path of the light beam as part of the beamconditioning assembly without departing from the scope of the invention.

As best seen in FIG. 3, the light beam 24 exits the top housing 104through an output window 38 provided underneath the top housing 104. Theoutput window 38 is preferably made of polyethylene, glass, or othersuitably transparent material. The output window 38 can advantageouslyprotect the optical components within the top housing 104 from dust orother contaminants. In some embodiments, the output window may beomitted.

The light beam 24 travels downward from the output window 38 towards thebase 102 of the casing 100, where it reaches a primary inspection window40 provided in the inspection counter 110 and vertically aligned withthe output window 38. The space immediately above the primary inspectionwindow 40 within the path of the light beam 24 defines the primaryinspection zone 42 for the mail to be inspected. The portion of thelight beam 24 transmitted through the mail to be inspected and theprimary inspection window 40 therefore contains imaging information onthe contents of the mail, which can be processed as explained furtherbelow. In some implementations, the primary inspection zone 42 has alarge imaging area. One example of an imaging area suitable for mailinspection can be around 9.5 inch by 7.125 inch. The primary inspectionwindow 40 may also be made of polyethylene, glass, or other suitablytransparent material. Preferably, the primary inspection window 40 has acurvature (best seen in FIGS. 4 and 5) designed to act as a field lensin order to collect more energy from the light beam 24 transmittedthrough the mail provided within the primary inspection space 42. Aswill be explained in further details below, the primary inspectionwindow 40 is preferably located at an imaging plane so that when anobject for inspection is placed in the primary inspection zone 42 itsimage will be in focus on the image sensor.

The mail screening apparatus 20 further includes a light redirectionassembly 45 provided in the base 102 and configured to redirect theinspection light beam 24 entering the base 102 from the primaryinspection zone 42 to emerge through the secondary inspection zone 50and project towards the top housing 104. Referring to FIGS. 3 and 5, inthe illustrated embodiment the light redirecting assembly 45 includes apair of folding mirrors 46 a and 46 b, mounted at opposite 45° angleswith respect to the plane of the inspection counter 110. The foldingmirrors 46 a and 46 b are preferably planar mirrors. Reflection on bothfolding mirrors 46 a and 46 b redirects the light beam 24 upwards at alocation offset the primary inspection zone 42, where it exits the base102 through a secondary inspection window 48 mounted in the inspectioncounter 110. The secondary inspection window 48 may also be made ofpolyethylene, glass, or other suitably transparent material. The spaceabove the secondary inspection window 48 within the path of the lightbeam 24 defines the secondary inspection zone 50, spanning a narrowerimaging area than the primary inspection zone 42. The mail to beinspected can therefore be placed in the secondary inspection zone 50 toprovide a zoomed image of a portion of the mail.

Referring again more particularly to FIG. 3, after crossing thesecondary inspection zone 50, the light beam re-enters the top housing104, which is preferably provided with an input window 52. The inputwindow 52 may also be made of polyethylene, glass, or other suitablytransparent material. In other variants the input window may be replacedby a suitably sized pass-through opening.

The mail screening apparatus 20 further includes a light collectingassembly 53 mounted in the top housing 104 and configured to receive anddetect the inspection light beam 24 projected from the base 102 throughthe secondary inspection zone 50. Still referring particularly to FIG.3, in the illustrated example the light beam 24 is collected by a cameraobjective 54. In one implementation, the camera objective 54 includes afast objective lens having an f-number (f/#) preferably lower thanf/1.2. A focus adjusting mechanism is provided to adjust the focus ofthe light collecting assembly 53 on either the primary or the secondaryinspection window 40 or 48, depending on the inspection zone being used.In the illustrated variant the focus adjusting mechanism is embodied bya rotating handle 56 operatively connected to the camera objective 54,but it will be readily understood that other means for setting thefocus, mechanically or electrically, can be used without departing fromthe scope of the invention.

Still referring to FIG. 3, the light collecting assembly 53 furtherincludes an image capture device 58 positioned to receive and detect thelight collected by the camera objective 54. The image capture device 58preferably comprises a 2D image sensor preferably sensitive in asuitable portion of the wavelength region spanning from 700 μm to 1075μm and preferably with a resolution of at least 320×240 pixels. Anexample of a suitable image sensor is the one used in the IRXCAM-384THzcamera module available from INO (Quebec, Canada), sensitive to the THzwaveband.

Referring now to FIGS. 2 and 3, the mail screening apparatus 20 mayfurther include at least one metal detection zone. In the illustratedembodiment first and second metal detection zones 60 and 62 are setalong the inspection counter 110 and orthogonally disposed with respectto the primary inspection zone 42. In the illustrated embodiment, thefirst metal detection zone 60 extends on the left side of the primaryinspection zone 42, opposite to the secondary inspection zone 44, andthe second metal detection zone 62 extends at the rear of the primaryinspection zone 42. In one implementation, each metal detection zone iscomposed of a mosaic of smaller metal detectors, each overlapping toensure complete inspection of the mail. Examples of suitable metaldetectors can for example be custom printed circuit boards of coils orinductances. Analysis of the electric signal from the metal detectorsmay be performed on the electronic board 66 provided with an analysisintegrated circuit, such as for example a Texas Instrument LDC1614. Dataanalysis from the metal detectors may for example be performed accordingto an operation similar to that used by the Scanmail 10K system fromScanna(http://www.scanna-msc.com/uk/shop/letterbomb-detector-mailscanner-scanmail-10k/).

As best seen in FIG. 1A, a display 64 is preferably provided to allow auser to visualize the inspection results of a piece of mail positionedin either one of the inspection zones 42, 50 or metal detection zones60, 62. The display 64 is preferably integrated in a front portion ofthe top housing 104 for easy viewing by a user positioned in front ofthe mail screening apparatus 20. The display may be embodied by a LCDscreen, a touchscreen, etc. The display 64 may be mounted on the tophousing 104 so as to be pivotable along at least one axis, to adapt tothe position of the user in front of the mail screening apparatus 20. Insome implementations, the display 64 may be omitted from the mailscreening apparatus and a connection to a separate visualizing devicemay be provided instead.

Referring again to FIGS. 3 and 5, the mail screening apparatus furtherincludes an electronic board 66. The electronic board 66 is configuredto perform a variety of control functions, such as, non-limitatively:

-   -   a. Acquiring the image data from the image capture device;    -   b. Preprocessing and formatting of the image data;    -   c. Acquiring the data from the metal detectors.

A processing unit 68 is preferably provided on the electronic board 66and is provided with operating software configured to perform variousprocessing functions, such as, non-limitatively:

-   -   a. Postprocessing of the image data acquired by the image        capture device (e.g. edge enhancement);    -   b. Processing of the information from the metal detectors;    -   c. Generating an alarm when the response of the metal detector        is above a given threshold;    -   d. Displaying of the acquired and processed images on the        display;    -   e. Saving the images in memory;    -   f. Linking the system to an ethernet output for remote control.

It will be readily understood that the electronic board and processingunit may be embodied by a variety of devices, modules and combinationsthereof without departing from the scope of the invention. In someembodiments, some or all of the processing functions may be performed byan external processor in communication with the mail screeningapparatus.

The mail screening apparatus 20 may be provided with any suitable userinterface components providing for an easy interaction with a user. Inone example, the display 64 may be embodied by a touchscreen configuredto provide the user with controls and options for using the mailscreening apparatus 20. Alternatively or additionally, the mailscreening apparatus 20 may be provided with keys, buttons, switches,pads, or any other user interface implements well known in the art.

Advantageously, the mail screening apparatus as described above can beoperable in either a “Normal” or a “Zoomed” mode. In the Normal mode, apiece of mail to be inspected is positioned in the primary inspectionzone 42, and the focus of the camera objective 54 is adjusted so thatthe image of the primary inspection window 40 is in focus on the imagecapture device 58. The secondary inspection zone is left free of anyobstruction, so that the light beam 24 reaching the image capture device58 provides images of the contents of the mail disposed in the primaryinspection zone 42. Similarly, in the Zoomed mode a piece of mail to beinspected is positioned in the secondary inspection zone 44, the focusof the camera objective 54 is adjusted so that the image of thesecondary inspection window 48 is in focus on the image capture device58. In this case the primary inspection zone 42 is left free of anyobstruction.

The piece of mail to be inspected can also be positioned on one of themetal detection zones 60 or 62 to detect the presence of metal partsenclosed within. In one embodiment, an alarm can be triggered when metalis indeed detected. The alarm can be a visual indication on the display,an audio alarm or any other means of communicating the information to auser.

Advantageously, the orthogonal configuration of the metal detectionzones with respect to the THz imaging primary inspection zone canaccommodate for both manual and automatic inspection of mail.

In one implementation, manual inspection of a piece of mail can beperformed from left to right, with a user first placing the piece ofmail on the first metal detection zone 60, receiving an indication ofthe presence of metal if it is indeed the case. The user then moves thepiece of mail to the primary inspection zone 42, adjusting the focus ofthe camera objective if necessary. An image of the contents of the pieceof mail is displayed on the display for the user to review. Optionally,for example if the overall image of the mail seems to indicatesuspicious contents in a particular area of the piece of mail, the usercan move the mail to the secondary inspection zone 44 with the area ofinterest aligned with the secondary inspection window 48, againadjusting the focus of the camera objective as necessary. A zoomed imageof the area of interest is presented on the display.

Automatic inspection of mail using the mail inspection apparatusdescribed above may for example be provided by mounting a conveyor belt(not shown) on the apparatus moving mail for inspection from rear tofront (or front to rear) over the inspection counter 110, first passinga given piece of mail over the second metal detection zone 62 and thenover the primary inspection zone 42. Mail for inspection can be fed tothe conveyor belt manually or from a separate automated conveyingdevice. In this mode, the secondary inspection zone 50 is left free ofany obstruction. If suspicious contents are detected, the automaticfeeding of mail for inspection can be interrupted and/or the piece ofmail ejected. The primary inspection zone 42 can be cleared and thesuspicious piece of mail can be inspected manually in the zoomed mode,as explained above.

Of course, numerous modifications could be made to the embodimentsdescribed above without departing from the scope of the invention.

1. An object detection apparatus, comprising: a casing with aninspection bay; a coherent light generating assembly configured togenerate a coherent light beam; a coherence breaking optical element forinteracting with the coherent light beam and projecting a brokencoherence light beam into an object inspection zone, the objectinspection zone defined by a path of the broken coherence light beam andthe inspection bay; a light collecting assembly positioned andconfigured to receive light resulting from the interaction of an objectwithin the object inspection zone and the broken coherence light beam; asensor to receive light from the light collecting assembly and sensitiveto the broken coherence light beam for producing image datarepresentative of object contents; and an electronic board configured toprocess the image data.
 2. The object detection apparatus according toclaim 1, wherein the coherence breaking optical element is a mirror. 3.The object detection apparatus according to claim 1, wherein thecoherence breaking optical element is rotated about a rotation axisnormal to its reflecting surface.
 4. The object detection apparatusaccording to claim 1, wherein the coherence breaking optical element isa reflective surface with a structured pattern.
 5. The object detectionapparatus according to claim 4, wherein the structured pattern comprisesa plurality of sloped elements distributed over the reflecting surface,each sloped element deviating a beam component of the coherent lightbeam incident thereon at a slightly different angle than the deviationimparted on neighboring beam components by neighboring sloped elements.6. The object detection apparatus according to claim 5, wherein a slopeof each sloped element may be computed to deviate the beam component ofthe coherent light beam incident thereon by an angle smaller than thedivergence of the coherent light beam.
 7. The object detection apparatusaccording to claim 1, wherein the coherent light beam corresponds to anoptical wavelength range between 50 μm and 3 mm.
 8. The object detectionapparatus according to claim 1, further comprising a beam conditioningassembly configured to transform the spatial energy distribution of thebroken coherence light beam into a flat-top final shape with arectangular footprint in the object inspection zone.
 9. An objectdetection apparatus, comprising: a casing with a light generatingassembly and a light collecting assembly; wherein the light generatingassembly generates an inspection light beam having a light beam pathwhich passes through a first inspection zone and a second inspectionzone to the light collecting assembly; a coherence breaking opticalelement for interacting with the inspection light beam and projecting abroken coherence inspection light beam into the first inspection zone;the light collecting assembly configured to receive light resulting fromthe interaction of objects within the first inspection zone and secondinspection zone and the broken coherence inspection light beam, thelight collecting assembly comprising a sensor sensitive to the brokencoherence inspection light beam for producing image data representativeof object contents; and an electronic board configured to process theimage data.
 10. The object detection apparatus according to claim 9,further comprising a focus mechanism whereby a focus of the lightcollecting assembly is located in the first inspection zone and a secondfocus of the light collecting assembly is located in the secondinspection zone, thereby enabling in focus imaging of an object in thefirst inspection zone and the second inspection zone.
 11. The objectdetection apparatus according to claim 10, wherein the focus of thelight collecting assembly in the second inspection zone is located at aninspection counter, thereby enabling in focus imaging of an object onthe inspection counter.
 12. The object detection apparatus according toclaim 10, wherein the focus of the light collecting assembly in thefirst inspection zone is located at an inspection counter, therebyenabling in focus imaging of an object on the inspection counter. 13.The object detection apparatus according to claim 9, further comprisinga lens between the first inspection zone and the second inspection zone.14. The object detection apparatus according to claim 9, wherein thecoherence breaking optical element is rotated about a rotation axisnormal to its reflecting surface.
 15. The object detection apparatusaccording to claim 9, wherein the coherence breaking optical element isa mirror.
 16. The object detection apparatus according to claim 15,wherein the mirror is a reflective surface with a structured pattern.17. The object detection apparatus according to claim 16, wherein thestructured pattern comprises a plurality of sloped elements distributedover the reflecting surface, each sloped element deviating the beamcomponent of the inspection light beam incident thereon at a slightlydifferent angle than the deviation imparted on neighboring beamcomponents by neighboring sloped elements.
 18. The object detectionapparatus according to claim 17, wherein the slope of each slopedelement may be computed to deviate the beam component of the inspectionlight beam incident thereon by an angle smaller than the divergence ofthe inspection light beam.
 19. The object detection apparatus of claim9, further comprising a metal detector wherein an automatic inspectionof objects is performed concurrently with the inspection of objects withthe metal detector.
 20. The object detection apparatus of claim 9,wherein the first inspection zone is used for the automatic inspectionof objects and the second inspection zone is used for the inspection ofobjects when objects are not present in the first inspection zone.